CN107589622B - Zero-order diffraction adjustable laser projection device - Google Patents
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- CN107589622B CN107589622B CN201710788366.3A CN201710788366A CN107589622B CN 107589622 B CN107589622 B CN 107589622B CN 201710788366 A CN201710788366 A CN 201710788366A CN 107589622 B CN107589622 B CN 107589622B
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Abstract
The invention discloses a laser projection device with adjustable zero-order diffraction, which comprises: a light source emitting light beams outward; a substrate for fixing the light source; the collimation unit converges the light beams emitted by the light source and projects parallel light beams outwards; the diffraction optical element receives and expands the parallel light beams and projects patterned light beams outwards, and the patterned light beams comprise zero-order diffraction light beams and high-order diffraction light beams; and the adjustable zero-order suppression unit is used for receiving and attenuating the zero-order derivative light beam and projecting an intensity-adjustable zero-order diffraction light beam outwards. The adjustable zero-order suppression unit comprises a polarizer, a half-wave plate device and an analyzer, or at least one rotatable polarizer and a rotatable analyzer. The zero-order diffraction adjustable laser projection device can accurately attenuate or shield the zero-order diffraction of the laser projection device according to requirements.
Description
Technical Field
The invention relates to the technical field of optics and electronics, in particular to a laser projection device with adjustable zero-order diffraction.
Technical Field
Laser projection apparatuses are used in various fields. For example, in the field of optical-based three-dimensional measurement, a laser projection device may be used to project a coded or structured laser pattern to a target space, so as to calibrate the target space and provide a preparation for later three-dimensional measurement. Laser projection devices generally consist of a substrate, a light source, a collimating unit, a diffractive optical element for generating and projecting a coded or structured laser pattern into a target space. The uniformity and high contrast of the patterned light beam projected into the target space directly affect the accuracy and sensitivity of the laser projection device in calibrating the depth of the target space.
However, diffractive optical elements used to generate laser patterns tend to present a zero order diffracted beam. The zero-order diffraction beam refers to a beam which is emitted to the diffractive optical element, and a part of the beam which is not diffracted and continues to pass through the diffractive optical element to enter the target space exists, namely the part of the beam which directly enters the target space without being diffracted by the diffractive optical element is the zero-order diffraction beam. Due to the zero-order diffraction problem of the diffractive optical element, the uniformity and contrast of the laser pattern projected to the target space by the laser projection device are reduced to different degrees, so that the laser projection device cannot be applied to some special application environments. In particular, in some applications of human-computer interaction based on laser projection devices, the zero-order diffracted beam of the laser projection device may cause eye safety problems. If the unit cross-sectional energy of the zero-order diffracted beam of the laser projection device exceeds the maximum allowable value of the laser light for the safety standard of human eyes, the laser projection device should not be used in an application environment involving human-computer interaction.
In the prior art, a scattering sheet with a surface perpendicular to the transmission direction of light beams is arranged in front of or behind a diffraction optical element, so that zero-order diffraction light beams can be reduced. Despite the above prior art, the scattering sheet mentioned in the technical solution is not suitable for being applied in a laser projection device of a depth camera, because the zero order diffracted beam scattered by the scattering sheet interferes with the distribution of the high order diffracted beam, thereby causing the accuracy of the depth camera to decrease, and therefore the technical solution is not suitable for a laser projection device projecting a coded or structured beam.
Disclosure of Invention
The invention provides a laser projection device with adjustable zero-order diffraction, aiming at solving the technical problem that zero-order diffraction beams with larger intensity exist in a diffraction optical element of the laser projection device.
In order to solve the above problems, the technical solution adopted by the present invention is as follows:
a laser projection device with tunable zero order diffraction, comprising: a light source emitting light beams outward; a substrate for fixing the light source; the collimation unit converges the light beams emitted by the light source and projects parallel light beams outwards; the diffraction optical element receives and expands the parallel light beams and projects patterned light beams outwards, and the patterned light beams comprise zero-order diffraction light beams and high-order diffraction light beams; and the adjustable zero-order suppression unit is used for receiving and attenuating the zero-order derivative light beam and projecting an intensity-adjustable zero-order diffraction light beam outwards.
The adjustable zero-order suppression unit comprises a polarizer and an analyzer, and the polarizer and/or the analyzer can rotate; the included angle between the transmission vibration direction of the polarizer and the transmission vibration direction of the analyzer is 0-90 degrees; the cross-sectional area of the polarizer and the cross-sectional area of the analyzer are not smaller than the cross-sectional area of a light spot of the zero-order diffracted light beam, and the polarizer and the analyzer comprise linear polaroids.
The adjustable zero-order suppression unit further comprises a half-wave plate device, wherein the half-wave plate device is positioned between the polarizer and the analyzer; the half-wave plate device comprises a rotary mirror bracket and a half-wave plate, wherein the rotary mirror bracket comprises an outer ring, a rotary body and an inner ring with a groove, and the outer ring is connected with the inner ring through the rotary body; the groove of the inner ring is used for fixing the half-wave plate; the azimuth angle of the half-wave plate optical axis is accurately controlled by rotating the rotatable mirror bracket.
A method for manufacturing a laser projection device with adjustable zero-order diffraction comprises providing a substrate and a light source, fixing the light source on the substrate; providing a collimation unit and a diffraction optical element, fixing the collimation unit between the light source and the diffraction optical element, and collimating or focusing the light beam emitted by the light source and projecting a parallel light beam to the diffraction optical element; the diffraction optical element is used for receiving and expanding the parallel light beams and projecting patterned light beams to a target space; and providing an adjustable zero-order diffraction suppression unit, wherein the adjustable zero-order diffraction suppression unit comprises a polarizer, a polarization analyzer or a half-wave plate device, and is arranged on one side of the light beam emitted by the diffraction optical element and used for accurately and adjustably shielding or attenuating the zero-order diffraction light beam in the patterned light beam.
The invention has the beneficial effects that: laser emitted by the light source is converged by the collimation unit and then emitted to the diffractive optical element in a parallel light beam mode, then the diffractive optical element expands the parallel light beam into a first laser pattern and emits the first laser pattern to the adjustable zero-order inhibition unit, and accurate attenuation processing can be effectively carried out on zero-order diffraction light beams in the first laser pattern based on the optical rotation effect and the extinction mechanism of the adjustable zero-order inhibition unit, so that the integrity of the laser speckle pattern is ensured, and the quality of the laser speckle pattern projected to a target space is further improved; the laser speckle pattern projected by the laser projection device has the characteristics of higher uniformity and higher contrast, and is more in line with the human eye safety standard.
Drawings
FIG. 1 is a schematic diagram showing the optical rotation of linearly polarized light by a half-wave plate according to an embodiment of the present invention.
Fig. 2 is a schematic top view of a rotatable frame according to an embodiment of the invention.
Fig. 3 is a cross-sectional structural view of a rotatable frame in accordance with an embodiment of the present invention.
FIG. 4 is a schematic diagram of a zero-order diffraction tunable laser projection apparatus according to an embodiment of the present invention.
FIG. 5 is a schematic diagram of a zero-order diffraction tunable laser projection apparatus according to another embodiment of the present invention.
Wherein, 1-natural light, 2-polaroid, 3-linearly polarized light beam, 4-half-wave plate, 5-emergent polarized light beam, 6-rotating mirror bracket, 61-outer ring, 62-rotating body, 63-inner ring, 64-light action object, 10-substrate, 11-light source, 12-collimation unit, 13-diffraction optical element, 100-adjustable zero order inhibition unit, 101-another adjustable zero order inhibition unit, 14-zero order diffraction light beam, 141-second zero order diffraction light beam, 142-third zero order diffraction light beam, 143-fourth zero order diffraction light beam, 144-another third zero order diffraction light beam, 15-polarizer, 151-linear polaroid of polarizer, 152-transparent part of polarizer, 16-half-wave plate device, 161-rotating mirror mount for half-wave plate arrangement, 162-half-wave plate, 17-analyzer, 171-linear polarizer for analyzer, 172-transparent part for analyzer, 18-higher order diffracted beam, 19-target plane, 191-higher order diffracted beam projection zone, 192-zero order diffracted beam projection zone, 20-rotatable analyzer, 201-linear polarizer for rotatable analyzer, 201-transparent part for rotatable analyzer, 203-rotating mirror mount for rotatable analyzer.
Detailed description of the preferred embodiments
The present invention will be described in detail below with reference to the following embodiments in order to better understand the present invention, but the following embodiments do not limit the scope of the present invention. It should be noted that the drawings provided in the following embodiments are only for illustrating the basic concept of the present invention, and the drawings only show the components related to the present invention rather than the number, shape and size of the components in actual implementation, the shape, number and proportion of the components in actual implementation can be changed freely, and the layout of the components can be more complicated.
It is to be understood that the terms "upper", "lower", "front", "rear", "inner", "outer", "left", "right", and the like, are used for indicating orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing embodiments of the present invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.
Fig. 1 is a schematic diagram of the optical action of a half-wave plate on linearly polarized light. The half-wave plate is processed by a birefringent crystal with a certain thickness, and can cause incident polarized light, and the ordinary light and the extraordinary light components of the incident polarized light to generate half-wavelength optical path difference or 180-degree phase retardation. In addition, a half-wave plate may be used to rotate the polarization direction of linearly polarized light. When the included angle between the polarization direction of the linearly polarized light beam which is incident perpendicular to the main section of the half-wave plate and the optical axis of the half-wave plate is alpha, the polarization direction of the emergent linearly polarized light beam rotates by an angle of 2 alpha relative to the polarization direction of an incident light beam. As shown in fig. 1, the light beam emitted from the light source has a polarization state similar to that of natural light, and has a symmetrical and uniform distribution. The natural light 1 is transmitted along the z-axis direction, when the natural light 1 is transmitted to the polarizer 2, since the polarization direction of the polarizer 2 is the y-direction, only the linearly polarized light beam 3 polarized along the y-axis direction can pass through the polarizer 2 smoothly and continue to be transmitted along the z-axis direction, and the light beams in other polarization directions are shielded and absorbed by the polarizer 2. When the polarized light beam 3 is incident on the half-wave plate 4, the angle between the polarization direction of the linearly polarized light beam 3 and the optical axis 41 of the half-wave plate 4 is
The polarization direction of the outgoing polarized light beam 5 relative to the incoming linearly polarized light beam 3 appears
The rotation of (2).
Fig. 2 is a schematic top view and fig. 3 is a schematic cross-sectional view of a rotatable frame according to an embodiment of the present invention. As shown in the figure, the rotary frame 6 is composed of an outer ring 61, a rotary body 62 and an inner ring 63 with a groove; wherein the groove of the inner ring 63 is used to embed and fix the light effect object 64 to be rotated. The outer ring 61 and the inner ring 63 are connected through a rotating body 62 to realize a linkage function. In one embodiment, the rotating body 62 is formed by threads engaged up and down, the inner ring 63 and the outer ring 61 are fixed on the inner side and the outer side of the rotating body 62 by gluing, welding or other feasible methods, and the outer ring 61 is rotated to cause the upper threads of the rotating body 62 to generate torsion to force the lower threads to rotate in the opposite direction, so that the rotation of the inner ring 63 is indirectly realized, and finally the purpose of accurately changing the rotation angle of the light action object 64 is achieved. It is emphasized that in order to meet the requirement of high precision adjustable rotation of the optically active object 64, the upper and lower intermeshing threads of the rotator 62 should be evenly and equidistantly distributed.
In an alternative embodiment of the invention, the light influencing object 64 may be a half-wave plate, and may also be a polarizer or analyzer.
Fig. 4 is a schematic diagram of a laser projection apparatus with adjustable zero-order diffraction according to an embodiment of the present invention. The laser projection apparatus in this embodiment includes a substrate 10, a light source 11, a collimating unit 12, a diffractive optical element 13, and a tunable zeroth-order suppression unit 100.
The light source 11 is fixed on one side of the substrate 10 facing the collimating unit 12 and emits a light beam to the collimating unit 12; the collimating unit 12 is configured to converge the light beam emitted from the light source 11 and project a parallel light beam toward the diffractive optical element 13; the diffractive optical element 13 is used for receiving and expanding the parallel light beams projected by the collimation unit 12 and projecting patterned light beams to the adjustable zero-order suppression unit 100; the patterned beam comprises a zero order diffracted beam 14 and a higher order diffracted beam 18; tunable zero-order suppression unit: receiving the patterned light beam, accurately attenuating or shielding the zero-order diffraction light beam in the patterned light beam, and projecting the high-order diffraction light beam in the patterned light beam and the attenuated or shielded zero-order diffraction light beam outwards. It is emphasized that expanding refers to expanding a single beam into multiple beams, which may also be referred to as splitting. The patterned beam formed by expanding the parallel beam may be a two-dimensional shape pattern, a two-dimensional spot pattern, or the like.
The tunable zero-order suppression unit 100 is composed of a polarizer 15, a half-wave plate device 16, and an analyzer 17, and is configured to flexibly shield and attenuate the intensity of the zero-order diffracted beam 14 and transmit the high-order diffracted beam 18 other than the zero-order diffracted beam 14.
The polarizer 15 comprises a linear polarizer 151 and a non-optical transparent part 152, wherein the linear polarizer 151 is embedded in the transparent part 152 in a sticking way, and the specific position and size are determined by the actual spot position and size of the zero-order diffraction light beam 14.
The half-wave plate device 16 is composed of a rotary mirror bracket 161 and a half-wave plate 162; at the position of the half-wave plate 162, the azimuth angle of the optical axis of the half-wave plate 162 can be accurately changed by rotating the rotary mirror holder 161;
the analyzer 17 is constructed substantially similarly to the polarizer 15, and includes a linear polarizer 171, a non-optically active transparent portion 172.
In one embodiment of the present invention, the transmission directions of the polarizer 15 and the analyzer 17 are parallel to each other, i.e. the transmission directions of the linear polarizer 151 and the linear polarizer 171 are the same, and the cross-sectional area is not smaller than the spot cross-sectional area of the zero-order diffracted beam 14, preferably, the cross-sectional areas of the linear polarizer 151 and the linear polarizer 171 are equal to the spot cross-sectional area of the zero-order diffracted beam 14.
The high-order diffracted beam 18 enters the tunable zero-order suppression unit 100 from the transparent portion 152 region of the polarizer 15, and since the high-order diffracted beam 18 is natural light, the high-order diffracted beam 18 can pass through the half-wave plate 162 without loss, and exits the tunable zero-order suppression unit 100 from the transparent portion 172 region of the analyzer 17, and is finally projected on the high-order diffracted beam projection region 191 of the target plane 19.
The zero-order diffracted light beam 14 is emitted into the adjustable zero-order suppression unit 100 from the area of the linear polarizer 151 of the polarizer 15, and the zero-order diffracted light beam 14 is emitted to the half-wave plate device 16 as the second zero-order diffracted light beam 141 after being polarized by the linear polarizer 151; then, after the second zero-order diffracted light beam 141 is subjected to optical rotation action by the half-wave plate 162, the polarization direction of the second zero-order diffracted light beam 141 can be deflected to a certain degree, and the third zero-order diffracted light beam 142 is emitted to the analyzer 17; since the transmission direction of the linearly polarizing plate 171 is the same as that of the linearly polarizing plate 151, a part of the energy of the third zero-order diffracted light beam 142 is absorbed by the linearly polarizing plate 171, and finally exits the tunable zero-order suppression unit 100 as the fourth zero-order diffracted light beam 143, and is projected on the zero-order diffracted light beam projection area 192 of the target plane 19.
Based on the optical rotation effect of the half-wave plate 162 and the extinction mechanisms of the polarizer 15 and the analyzer 17, the rotating mirror holder 161 is rotated to change the included angle α between the optical axis of the half-wave plate 162 and the polarization direction of the second zero-order diffracted light beam 141, so that the polarization direction of the third zero-order diffracted light beam 142 can be accurately deflected, and the light intensity of the zero-order diffracted light beam 14 can be accurately attenuated or regulated.
For ease of understanding, in particular, the light intensity of the zero-order diffracted light beam 14 is assumed to be I0The second zero-order diffracted beam 141 is attenuated to 0.5I after being polarized by the polarizing plate 1510Since the angle between the optical axis of the half waveplate 164 and the polarization direction of the second zero-order diffracted light beam 141 is α, the angle between the polarization direction of the third zero-order diffracted light beam 142 and the linear polarizer 151 and the linear polarizer 171 is 2 α, and the light intensity of the fourth zero-order diffracted light beam 143 projected onto the target plane 192 is 0.5I in combination with malus law0*(cos2α)2That is, the intensity of the fourth zero-order diffracted beam 143 is determined by the included angle α, and the value of the included angle α is adjusted to be in the range of 0 to 45 °. This has the advantage that the zero order diffracted beam 14 can be accurately attenuated by adjusting the azimuth angle of the optical axis of the half-wave plate device 16 according to the light intensity of the higher order diffracted beam 18, thereby ensuring a uniform distribution of the patterned laser beam projected to the target space.
In an alternative embodiment of the invention, the light source 11 may be an edge-emitting laser and its array or a vertical cavity surface-emitting laser and its array; the light source 11 is an infrared laser beam with the wavelength of 850nm and 950nm or a laser beam with other wave bands; the polarizer 15 may be constituted by only the linear polarizing plate 151 and fixed to the light outgoing side of the diffractive optical element 13 by means of embedding, bonding, or other feasible means; the analyzer 17 may be constituted only by the linearly polarizing plate 171, andand is fixed on the light-emitting side of the half-wave plate device 16 by embedding, pasting or other feasible ways. In this case, the cross-sectional areas of the polarizer 15 and the analyzer 17 should be not smaller than the spot area of the zero-order diffracted beam 14. Note that the fourth zero-order diffracted light beam 143 projected on the target plane 192 has an optical intensity I of 0.5I0*(cosα)2Wherein the value of the included angle alpha is adjusted within the range of 0-90 degrees.
In a further alternative embodiment of the invention, the polarizer 15 is at an angle β to the direction of transmission of the analyzer 17, i.e. the linear polarizer 171 is at an angle β to the linear polarizer 151. Wherein the value range of beta is 0-90 degrees. It should be noted that the fourth zero-order diffracted light beam 143 projected on the target plane 192 has an optical intensity I of 0.5I0*(cos(β-2α))2Or I is 0.5I0*(cos(2α-β))2I.e. the light intensity of the fourth zero order diffracted beam 143 is determined by both angles alpha and beta.
FIG. 5 is a schematic diagram of a zero-order diffraction tunable laser projection apparatus according to another embodiment of the present invention. The laser projection apparatus in this embodiment is substantially the same as the laser projection apparatus in the embodiment of fig. 4, except that the further adjustable zero-level suppression unit 101 of the laser projection apparatus includes: a polarizer 15 and a rotatable analyzer 20.
The polarizer 15 is similar to the structure of the embodiment of FIG. 4, and will not be described again.
The rotatable analyzer 20 comprises a linear polarizer 201, a non-optically active transparent portion 202, and a rotatable frame 203; the linear polarizer 201 is fixed in the transparent portion 202 by embedding, adhering or other feasible ways, and the specific position and size are determined by the position and size of the light spot of the zero-order diffracted light beam 14; the transparent part 202 is fixed in a recessed groove inside the rotating frame 203 in an embedded manner, and the transmission direction of the linearly polarizing plate 201 can be accurately changed by rotating the rotating frame 203.
In one embodiment of the present invention, the centers of the linearly polarizing plate 151 and the linearly polarizing plate 201 and the center of the zero-order diffracted light beam 14 are disposed on the same horizontal line, and the cross-sectional areas of the linearly polarizing plate 151 and the linearly polarizing plate 201 are not smaller than the spot cross-sectional area of the zero-order diffracted light beam 14, preferably, the cross-sectional areas of the linearly polarizing plate 151 and the linearly polarizing plate 201 are equal to the spot cross-sectional area of the zero-order diffracted light beam 14.
The high-order diffracted light beam 18 passes through the tunable zero-order suppression unit 101 from the polarizer 15 and the transparent portions 152 and 202 of the rotatable analyzer 20 and directly enters the target space, and is finally projected on the high-order diffracted light beam projection region 191 of the target plane 19.
The zero-order diffracted light beam 14 is emitted into the adjustable zero-order suppression unit 101 from the area of the linear polarizer 151 of the polarizer 15, and the zero-order diffracted light beam 14 is emitted to the area of the linear polarizer 201 of the rotatable analyzer 20 as a second zero-order diffracted light beam 141 after being polarized by the linear polarizer 151; after the second zero-order diffracted light beam 141 is acted on by the polarizing plate 201, it exits the tunable zero-order suppression unit 101 as the third zero-order diffracted light beam 142 and is projected on the zero-order diffracted light beam projection area of the target plane 19. Based on the extinction mechanism of the linear polarizer, the rotating frame 203 is rotated to change the transmission direction of the linear polarizer 201, so that the included angle alpha between the linear polarizer 201 and the linear polarizer 151 in the transmission direction is changed, and the purpose of accurately attenuating the light intensity of the zero-order diffracted light beam 14 is achieved.
For ease of understanding, in particular, the light intensity of the zero-order diffracted light beam 14 is assumed to be I0The second zero-order diffracted beam 141 is attenuated to 0.5I after being polarized by the polarizing plate 1510Because the linear polarizer 201 and the linear polarizer 151 form an angle α with respect to the transmission direction, the second zero-order diffracted light beam 141 is attenuated and absorbed by the linear polarizer 161, and then emitted to the target space as the third zero-order diffracted light beam 144, and the light intensity of the third zero-order diffracted light beam 144 projected to the region of the target plane 192 is 0.5I, in combination with malus law0*(cosα)2That is, the intensity of the third zero-order diffracted beam 144 is determined by the included angle α, and the value of the included angle α is adjusted to be in the range of 0 to 90 °. This has the advantage that the zero order diffracted beam 14 can be accurately attenuated by adjusting the transmission direction of the rotatable analyzer 20 according to the light intensity of the high order diffracted beam 18, thereby ensuring a uniform distribution of the patterned laser beam projected in the target space.
In an alternative embodiment of the invention, the linearly polarizing plate 151 polarizes the zero order diffracted beam 14 at any angle; the polarizer 15 may be constituted by only the linear polarizing plate 151 and fixed to the light outgoing side of the diffractive optical element 13 by means of embedding, bonding, or other feasible means; the adjustable analyzer may be comprised of only the linear polarizer 201 and the rotating frame 203.
In yet another alternative embodiment of the invention, the tunable zero-order suppression unit 101 comprises a polarizer and an analyzer, wherein the polarizer and/or analyzer can be rotated. Specifically, the tunable zero-order suppression unit 101 may be a combination of a rotatable polarizer and an analyzer, a combination of a polarizer and a rotatable analyzer, or a combination of a rotatable polarizer and a rotatable analyzer.
The laser projection device with adjustable zero-order diffraction can be integrated in a depth camera system, and based on the laser projection device with adjustable intensity of zero-order diffraction light beams, the laser speckle patterns projected by the projection device of the depth camera have the characteristic of more uniform brightness distribution, namely the speckle images acquired by the picture capture device of the depth camera system have higher accuracy, so that the performance of the depth camera is integrally improved, and the intensity of the laser patterns can be adjusted by the depth camera according to the safety regulation of human eyes.
Different from the prior art, the diffraction optical element of the traditional laser projection device has the problem of zero-order diffraction. The laser projection device designed by the invention can accurately attenuate the zero-order diffracted light beam according to the actual situation while ensuring the integrity of the laser speckle pattern by adding the adjustable zero-order inhibition unit, thereby further improving the overall quality of the laser speckle pattern.
On the basis of the present invention, it is desirable to adopt other optical elements in the prior art to reduce the intensity of zero-order diffraction in a laser projection device by attenuation or shielding.
In the laser projection apparatus with adjustable zero-order diffraction, none of the hardware installation methods described above should be regarded as limitations of the present invention, and the required hardware only needs to satisfy the sequential installation described in the present invention, and the specific installation manner may be the installation manner achievable in the prior art.
The tunable zero-order suppression unit of the present invention can also be applied to other devices for attenuating the intensity of zero-order diffraction, and the specific application thereof based on the idea of the present invention shall fall within the protection scope of the present invention.
In addition, the invention also provides a manufacturing method of the zero-order diffraction adjustable laser projection device, which comprises the steps of providing a substrate and a light source, and fixing the light source on the substrate; providing a collimating unit and a diffractive optical element, fixing the collimating unit between the light source and the diffractive optical element, and collimating or focusing the light beam emitted by the light source; the diffractive optical element is used for receiving and expanding the light beam and projecting a patterned light beam to a target space; and providing an adjustable zero-order suppression unit, wherein the adjustable zero-order suppression unit comprises a polarizer, an analyzer or a half-wave plate device, and is arranged on one side of the light beam emitted by the diffractive optical element and used for shielding or attenuating the zero-order diffracted light beam in the patterned light beam.
The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several equivalent substitutions or obvious modifications can be made without departing from the spirit of the invention, and all the properties or uses are considered to be within the scope of the invention.
Claims (9)
1. A laser projection device with adjustable zero-order diffraction, which is integrated in a depth camera system, is characterized by comprising:
a light source emitting light beams outward;
a substrate for fixing the light source;
the collimation unit converges the light beams emitted by the light source and projects parallel light beams outwards;
the diffraction optical element receives and expands the parallel light beams and projects patterned light beams outwards, and the patterned light beams comprise zero-order diffraction light beams and high-order diffraction light beams;
and the adjustable zero-order suppression unit is used for receiving the patterned light beam, accurately attenuating the zero-order derivative light beam through an optical rotation effect and an extinction mechanism, and projecting the high-order diffraction light beam in the patterned light beam and the intensity-adjustable zero-order diffraction light beam outwards without loss.
2. The tunable laser projection device of claim 1, wherein the tunable zero-order suppression unit comprises a polarizer and an analyzer.
3. The tunable laser projection device of claim 2, wherein the polarizer and/or the analyzer can be rotated.
4. The tunable laser projection apparatus according to claim 3, wherein the angle between the direction of the transmission of the polarizer and the direction of the transmission of the analyzer is 0-90 °.
5. The tunable laser projection device with zero-order diffraction of claim 2, wherein the tunable zero-order suppression unit further comprises a half-wave plate device located between the polarizer and the analyzer;
the half-wave plate device comprises a rotary mirror bracket and a half-wave plate, wherein the rotary mirror bracket comprises an outer ring, a rotary body and an inner ring with a groove, and the outer ring is connected with the inner ring through the rotary body; the groove of the inner ring is used for fixing the half-wave plate.
6. The zero order diffraction tunable laser projection device of claim 5, wherein the azimuth angle of the optical axis of the half-wave plate is precisely controlled by rotating the rotatable mirror mount.
7. The tunable laser projection apparatus of claim 2, wherein the cross-sectional area of the polarizer and the cross-sectional area of the analyzer are not smaller than the spot cross-sectional area of the zero-order diffracted beam.
8. The tunable zero-order diffraction laser projection device of claim 2, wherein the polarizer and the analyzer comprise linear polarizers.
9. A method for manufacturing a laser projection device with adjustable zero-order diffraction is characterized by comprising the steps of providing a substrate and a light source, and fixing the light source on the substrate; providing a collimation unit and a diffraction optical element, fixing the collimation unit between the light source and the diffraction optical element, and collimating or focusing the light beam emitted by the light source and projecting a parallel light beam to the diffraction optical element; the diffraction optical element is used for receiving and expanding the parallel light beams and projecting patterned light beams to a target space; and providing an adjustable zero-order diffraction suppression unit, wherein the adjustable zero-order diffraction suppression unit comprises a polarizer, a polarization analyzer or a half-wave plate device, and is arranged on one side of the light beam emitted by the diffraction optical element and used for accurately and adjustably shielding or attenuating the zero-order diffraction light beam in the patterned light beam.
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| CN201710788366.3A CN107589622B (en) | 2017-09-01 | 2017-09-01 | Zero-order diffraction adjustable laser projection device |
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| CN201710788366.3A CN107589622B (en) | 2017-09-01 | 2017-09-01 | Zero-order diffraction adjustable laser projection device |
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| CN107589622A CN107589622A (en) | 2018-01-16 |
| CN107589622B true CN107589622B (en) | 2020-11-03 |
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| WO2020164346A1 (en) * | 2019-02-14 | 2020-08-20 | 杭州驭光光电科技有限公司 | Beam-splitting optical module and manufacturing method therefor |
| US11977239B2 (en) * | 2020-07-10 | 2024-05-07 | Sumitomo Electric Hardmetal Corp. | Diffractive optical device |
| CN113219675B (en) * | 2021-04-01 | 2022-08-30 | 嘉兴驭光光电科技有限公司 | Diffraction optical element design method and laser projection module |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1916756A (en) * | 2005-08-18 | 2007-02-21 | 精工爱普生株式会社 | Lighting device and projector |
| CN101539664A (en) * | 2008-03-17 | 2009-09-23 | 索尼株式会社 | Irradiation optical system, irradiation apparatus and fabrication method for semiconductor device |
| CN103323958A (en) * | 2013-06-22 | 2013-09-25 | 夏云 | Speckle eliminating device based on cross polarization composition |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1916756A (en) * | 2005-08-18 | 2007-02-21 | 精工爱普生株式会社 | Lighting device and projector |
| CN101539664A (en) * | 2008-03-17 | 2009-09-23 | 索尼株式会社 | Irradiation optical system, irradiation apparatus and fabrication method for semiconductor device |
| CN103323958A (en) * | 2013-06-22 | 2013-09-25 | 夏云 | Speckle eliminating device based on cross polarization composition |
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